Vehicle seat with suspension and selective suspension lock-out

ABSTRACT

A resiliently suspended vehicle seat with means for selectively locking out the resiliency of the suspension to fix the seat against both up and down movement.

United States Patent Magruder et al.

[ Mar. 19, 1974 VEHICLE SEAT WITH SUSPENSION AND SELECTIVE SUSPENSIONLOCK-OUT Inventors: Michael Keith Magruder, Waterloo;

Terrill Wayne Woods, Cedar Falls, both of Iowa Assignee: Deere &Company, Moline, Ill.

Filed: June 26, 1972 Appl. No.: 265,976

US. Cl. 248/399 Int. CL... B60n 1/02 Field of Search 248/399, 400, 162,421

References Cited UNITED STATES PATENTS 4/1973 Swenson et a1, 248/399Manke 248/399 Eicher 248/399 Pillons et a1. 248/399 Swenson 248/399Primary Examiner-Marion Parsons, Jr.

ABSTRACT A resiliently suspended vehicle seat with means for selectivelylocking out the resiliency of the suspension to fix the seat againstboth up and down movement.

6 Claims, 6 Drawing Figures BACKGROUND OF THE INVENTION DESCRIPTION OFTHE PREFERRED EMBODIMENT A support member W of L shape has a horizontalIt is conventional in off-the-road vehicles, such as portion 12 adaptedin usual manner to be attached rigfarm tractors, road graders, scrapersand similar vehicles, to provide a seat suspended, typically byso-called parallel linkage combined with a spring and shockabsorberunit, for controlled and adjustable up and down movement of the rideraccording to such variables as rider size and weight, terrain, etc. Insome instances, the controlled up and down movement of the seat mayprove to be a temporary disadvantage; e.g., when the load on the seat isin excess of the ability of the suspension system to handle it, when theresiliency of the suspension is apt to cause undue upward movement, etc.In the former instance, as when the seat is designed primarily for oneperson but has provision for seating a second person in certaincircumstances, the combined weight of the two riders is such as todepress the seat to a level below that at which the driver can safelysee ahead.

In the latter instance, efforts have been made in the prior art toutilize secondary control means for limiting at least the upwardmovement of the seat so that the rider cannot be pitched from the seatduring excessively rough conditions, but none of these have operated onthe basis of fixing the seat, selectively, in a position in which thedriver's vantage point is insured.

SUMMARY OF THE INVENTION Broadly, the present invention provides aselective lock-out of the usual suspension so that the seat is fixedagainst movement both up and down out of a selected position, and morespecifically a position in which the driver retains full view of theroad, field, etc. ahead. What is achieved here is that the suspensionand lockout are so coordinated that the suspension may function in itsnormal manner but may be easily converted to a rigid system underselected conditions. The control or selector for choosing between normaland locked conditions is so designed that it may be pre-selected; i.e.,the locked condition may be selected even during downward or upwardpositions of the seat and final locking will occur automatically uponrelease or depression of the seat for movement to its upper or lowerpositions.

The last-named feature includes a control linkage that accommodatesnormal movement of the parts even though it has a biasing meansconditioning the lock-out for locking. The control itself, preferably inthe form of an easily accessible control member, is convenientlylocated, simple in construction and requires little if any maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of atypical seat and suspension in which the invention finds utility.

FIG. 2 is an enlarged view generally along the line 2-2 of FIG. 1.

FIG. 3 is a reduced-scale view of a two-man" seat as representative of acondition in which a suspension lock-out is desirable.

FIG. 4 is an enlarged 'view of parts of the lock-out.

FIG. 5 is a fragmentary view of a modification.

FIG. 6 is a fragmentary view of a further modification.

idly to a vehicle frame or body 14 and an upright leg 16 which hasvertically spaced pivots l8 and 20 for mounting the rear ends of a pairof upper and lower socalled parallel links 22 and 2d, the front ends ofwhich are pivotally connected at 26 and 28 to a seat member 30. Acombination spring and shock-absorber unit 32 completes a typical seatsuspension that carries the seat member 30 for up and down movement. Thelinks 22 and 24 may be regarded as members forming part of thesuspension means that includes the unit 32 as well as the links, pivots,etc.

As best seen in FIG. 3, the seat is relatively wide but is primarilyintended for one-man use by delineation of arm rests 34 and 36, thelatter of which is relatively wide and which may be swung upwardly andrearwardly, not only to make the total width of the seat available foran extra rider but to combine with a fixed seat back 38 to complete awide seat back. This feature is not part of the present invention but isdisclosed as an example to illustrate the desirability for a lock-outmeans. As will be appreciated, if the suspension means 22, 24, 32 isdesigned to accommodate a single rider, it will become overloaded by thepresence of two riders on the same seat, the result being that the seatwill be depressed to down position in which the driver does not havefull command of the view ahead. The solution is to retain the seat in anelevated condition; i.e., to prevent its undue depression underoverload.

This is achieved here by locking the seat in its up or near up positionby means that prevents the seat from moving in either vertical directionout of the locked position. Preferably this is accomplished by a singlesimple lock link 40 and a control 42.

The control is in the form of a bell-crank lever 44 pivoted to theupright part 16 of the support 10 at 46 for lateral swinging between anL (lock position) and an R" (release position). See FIG. 2. Forretaining the control against inadvertent movement out of its selectedposition, the pivot 46 includes any suitable reraining means, here aspring-loaded friction device 48.

The control is mounted centrally behind the seat back 38.

The lock link 40 is pivoted at its front end to the suspension means,here by means of a pivot 50 to the lower suspension link 24 and extendsrearwardly into proximity to a lug 52 and pin 54 fixed to the supportmeans member or leg 16, at which pointv the rear end of the link 40 isprovided with means selectively engageable with and disengageable fromthe support member 10. This means comprises, here, an elongated slot 56in the link 40 (FIG. 4) which has a shorter, angular slot 58 incommunication therewith. These slots are selectively engageable with thepin or guide 54. Normallyi.e., when the suspension is unlocked orreleased, the link 40 has relatively free movement as the link 40, viathe long slot 56, runs back and forth on the pin 54, the weight of thelink 40 causing the slot 56 to ride on its top edge on the pin 54. Thelength of the slot 56 is determined according to the fore-and-aftmovement required as the suspension links 22 and 24 move up and down.Thus, normally, the short slot 58 is free from engagement with the pin54.

When it is desired to lock the seat and its suspension as and for thepurposes already described herein, the link 40 is raised by the control42, accomplished here by a link including resilient means such as atension spring 60 (FIGS. 1, 2 and 4). This biases the link 40 upwardly,so that when the pin 54 and short slot 58 become alined, the link 40will move upwardly, under the force of the spring 60, to engage the slot58 with pin 54, thus locking the suspension against further movementuntil the control 42 is moved to its R" position. For example, shouldthe seat 30 be completely unloaded, the pin 54 will be at the forwardend of the slot 56 (FlG. 4) and the lever 42 be moved to its L position,the spring 60 will load the link 40 upwardly. When load is applied tothe seat, the link 40 will move rearwardly for about one-half the lengthof the slot 56 and the upward bias on the link 40 will cause the link toride on the pin 54 until the short slot 58 engages the pin 54.Conversely, should the seat be fully depressed, as by two riders, thepin 54 will be at the rear end of the long slot 56, but when the seatrises, the short slot 58 will engage the pin 54 because of the springload imposed by the spring 60. The point of engagement of the pin andslot 5458 is preferably selected on the basis of the ideal vantage pointof the driver, having respect to his view of the path, road, field,etc., ahead.

Although it is expected that the weight of the link 40 may be reliedupon to benefit from the force of gravity and thus cause the top edge ofthe slot 56 normally to ride the pin 54, besides which the tensionspring 60, usually "loose, may be expected to exert a downward force onthe link 40, it may be desirable to impose additional downward forces onthe link 40 during release" condition.

FIG. shows one way of doing this; ie, by adding a downward spring loadto the link 40, as by a torsion spring 62. Of course, the tension spring60 must be stronger than the spring 62. A further example is suggestedin FIG. 6, in which the spring 60 is supplemented by a guide 64 fixed tothe top of the link 40 to assure that at least some compressive forcewill be applied through the spring 60 in the release position of thecontrol 42.

We claim:

1. A vehicle seat structure having a support member,

a rider-carrying seat member, and yielding suspension means including amovable member carrying the seat member on the support member forrelative up and down movement, characterized by lock means forselectively positively locking the seat member against both up and downmovement and for releasing the seat member for up and down movement,said lock means including an element pivoted on and carried by onemember and having an elongated slot therein and a second slot angled tothe elongated slot, another member has a guide carrying the element bymeans of the elongated slot when the seat member is released for up anddown movement, and control means for effecting relative shiftingmovement between said element and guide for receipt of the guide in theangled slot so as to lock the seat member against up and down movement.

2. The invention defined in claim 1, further characterized in that theelement is biased so that the top edge of the elongated slot normallyrides on the guide, the angled slot depends from the elongated slot, andthe control means is operative to elevate the element relative to theguide to receive the latter for locking the seat member.

3. The invention defined in claim 1, further characterized in that theelement is so pivoted to the one member that it tends to swingdownwardly by gravity, the top edge of the elongated slot normally rideson the guide, the angled slot depends from the elongated slot. and thecontrol means is operative to elevate the element relative to the guideto receive the latter for locking the seat member.

4. The invention defined in claim 3, in which the control means ismovable between lock and release positions, a link means is connectedbetween the control means and the element to move the element upwardlywhen the control means is moved to its lock position.

5. The invention defined in claim 4 in which the link means includes aresilient connection for imparting a lifting bias to the element whenthe control means is moved to its lock position.

6. The invention defined in claim 4, further characterized in thatreleasable means is provided for holding the control means in its lockposition.

1. A vehicle seat structure having a support member, a ridercarryingseat member, and yielding suspension means including a movable membercarrying the seat member on the support member for relative up and downmovement, characterized by lock means for selectively positively lockingthe seat member against both up and down movement and for releasing theseat member for up and down movement, said lock means including anelement pivoted on and carried by one member and having an elongatedslot therein and a second slot angled to the elongated slot, anothermember has a guide carrying the element by means of the elongated slotwhen the seat member is released for up and down movement, and controlmeans for effecting relative shifting movement between said element andguide for receipt of the guide in the angled slot so as to lock the seatmember against up and down movement.
 2. The invention defined in claim1, further characterized in that the element is biased so that the topedge of the elongated slot normally rides on the guide, the angled slotdepends from the elongated slot, and the control means is operative toelevate the element relative to the guide to receive the latter forlocking the seat member.
 3. The invention defined in claim 1, furthercharacterized in that the element is so pivoted to the one member thatit tends to swing downwardly by gravity, the top edge of the elongatedslot normally rides on the guide, the angled slot depends from theelongated slot, and the control means is operative to elevate theelement relative to the guide to receive the latter for locking the seatmember.
 4. The invention defined in claim 3, in which the control meansis movable between lock and release positions, a link means is connectedbetween the control means and the element to move the element upwardlywhen the control means is moved to its lock position.
 5. The inventiondefined in claim 4 in which the link means includes a resilientconnection for imparting a lifting bias to the element when the controlmeans is moved to its lock position.
 6. The invention defined in claim4, further characterized in that releasable means is provided forholding the control means in its lock position.